Turner said the loss appears to be a combination of erosion and sloughing, which can't be addressed until state engineers finish the geotechnical fact-finding and analysis. Officials hope that will identify the causes as well as provide a timeline for future losses.

The Army Corps of Engineers says the loss hasn't weakened the stability of the floodwall stability. Turner agrees, but he said corps representatives also agreed recently that more investigation is needed. And when they didn't promptly respond with a plan, Turner said he asked the state for help.

The canal bank has lost an average of 6 to 8 inches of land since it was first noticed and documented by the East Jefferson Levee District in mid-2007. But in some spots more than 18 inches is missing, records show.

Commissioners agreed that wrangling with the corps over who pays for what remedial action shouldn't delay a response.

"Somebody has to bite the bullet - us or the state or the corps or a combination - and get it done," said levee commissioner Ricardo Pineda, a water resources director for the state of California.

The land loss is occurring mostly between Veterans Memorial Boulevard and Cotton Street.

"We feel ... the erosion is the result of something that's happened in the canal since Hurricane Katrina," said Executive Director Fran Campbell of the East Jefferson Levee District. "And we want to know what."

"Everybody also needs to remember that the corps set the safe-water elevation in the canal three years based on how it existed at the time," she said. "We want to know if the erosion has affected the level, or will it in the future. And what should we be looking for? What will indicate that the safe water level is changing?". . . . . . .

Sheila Grissett can be reached at sgrissett@timespicayune.com or 504.717.7700.